This invention relates to methods of making heat exchangers and, more particularly, to methods of making heat exchangers having outwardly projecting fins spaced longitudinally therealong, and wherein both of the longitudinally facing faces of the fins have roughened surfaces.
It is a primary object of the present invention to afford a novel method of making a heat exchanger.
Another object is to afford a novel method of making a heat exchanger wherein external fins are formed by cutting or gouging the same from wall portions of the heat exchanger.
Another object of the present invention is to afford a novel method of making a heat exchanger of the spined type and wherein the spines are formed from outwardly projecting ribs on the heat exchanger.
A further object of the present invention is to afford a novel method of making a heat exchanger of the spined type wherein the spines are formed as integral parts of larger fin members by cutting or gouging the spines from outwardly projecting ribs and cutting or gouging the remainder of the fin members from material underlying the ribs.
The making of spined heat exchangers by cutting or gouging the spines from outwardly projecting ribs on a tubular member has been heretofore known in the art, being shown, for example, in my earlier U.S. Pat. No. 3,202,212, issued Aug. 24, 1965; and in U.S. Pat. Nos. 3,866,286, issued to Stephen F. Pasternak, on Feb. 18, 1975; 3,886,639, issued to Stephen F. Pasternak, on June 3, 1975; and 3,947,941, issued to Joseph M. O'Connor, on Apr. 6, 1976.
Also, making of spined heat exchangers wherein the spines are formed as integral parts of a larger fin member by cutting or gouging the spines from outwardly projecting ribs and cutting or gouging the remainder of the fin members from material underlying the ribs has been heretofore known in the art, being shown, for example, in U.S. Pat. No. 3,693,105, issued to Joseph M. O'Connor, on Sept. 19, 1972, and in my co-pending application for U.S. Pat. No. 205,795 filed Nov. 10, 1980.
It is an important object of the present invention to afford a novel method of forming finned and/or spined heat exchangers.
It is known that in the making of finned and/or spined heat exchangers in accordance with the teachings of all of the aforementioned patents and the aforementioned patent application, the faces of the fins, facing in the direction of the travel of the cutting tool in the making of the cut, are substantially roughened. Such roughening commonly is in the nature of bubbles having a thickness of 0.001 to 0.002" on fins having an over-all thickness of 0.009". This, in spite of the fact that the reverse sides of such fins, and the underlying surfaces of the work-piece, from which the fins have been cut or gouged, are shiny smooth in nature. It is my opinion that such roughening of the one side of such fins is caused by the thickening and foreshortening of the fins during the gouging action cuts of substantially less thickness (such as 0.003") and of greater length (such as 1.125") being used to produce fins of substantially greater thickness (such as 0.009") and lesser length (such as 0.4").
It has been found that even having the one roughened surface on such fins is advantageous in a heat transfer member, affording a greater heat-transfer surface area; assisting in breaking up laminar flow past the fins; creating turbulence in the working fluid passing between the fins; and tending to break up the boundary layers of working fluid disposed immediately adjacent to such roughened surfaces.
It is an important object of the present invention to increase such advantageous performances of heat transfer members by enabling both sides of such fins to be roughened.
Another object of the present invention is to afford a novel method of making finned and/or spined heat exchangers wherein both opposite sides of the fins and/or spines are roughened.
Another object of the present invention is to afford a novel method of making finned and/or spined heat exchangers of the aforementioned type, wherein the work-pieces and cutters are vibrated relative to each other in a novel and expeditious manner during the forming of such fins and/or spines.
A further object of the present invention is to afford a novel method of making finned and/or spined heat exchangers of the aforementioned type wherein the cutter is vibrated relative to the work-piece during a cutting or gouging operation.
Another object of the present invention is to afford a novel method of making a finned and/or spined heat exchanger of the aforementioned type wherein the work-piece is vibrated relative to the cutter during a cutting or gouging operation.
Another object of the present invention is to afford a novel method of making heat exchangers which is effective to afford, in a novel and expeditious manner, increased turbulence in air or other working fluid passing across the completed heat exchanger.
Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by way of illustration, show preferred embodiments of the present invention and the principles thereof and what I now consider to be the best modes in which I have contemplated applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.